The VERT-X calibration facility: development of the most critical parts.

The ATHENA X-ray telescope will be the largest X-ray optics ever built. The ground calibration of this mirror assembly raises significant difficulties due to its unprecedented size, mass and focal length. The VERT-X project aims at developing an innovative calibration system which will be able to accomplish to this extremely challenging task.The design is based on an X-ray parallel beam produced by an X-ray source positioned in the focus of a highly performing X-ray collimator; the beam will be accurately moved by a raster-scan mechanism covering all the ATHENA optics at different off-axis angles. The main driving factor in the VERT-X design is the ATHENA calibration requirement on the accuracy in the HEW measure which is 0.1”, all over the field of view. The VERT-X project, started in January 2019, is financed by ESA and conducted by a consortium that includes INAF together with EIE, Media Lario, BCV Progetti and GPAP.